Commit message: nfc: nfcmrvl: main: reorder destructive operations in nfcmrvl_nci_unregister_dev to avoid bugs

There are destructive operations such as nfcmrvl_fw_dnld_abort and
gpio_free in nfcmrvl_nci_unregister_dev. The resources such as firmware,
gpio and so on could be destructed while the upper layer functions such as
nfcmrvl_fw_dnld_start and nfcmrvl_nci_recv_frame is executing, which leads
to double-free, use-after-free and null-ptr-deref bugs.

There are three situations that could lead to double-free bugs.

The first situation is shown below:

   (Thread 1)                 |      (Thread 2)
nfcmrvl_fw_dnld_start         |
 ...                          |  nfcmrvl_nci_unregister_dev
 release_firmware()           |   nfcmrvl_fw_dnld_abort
  kfree(fw) //(1)             |    fw_dnld_over
                              |     release_firmware
  ...                         |      kfree(fw) //(2)
                              |     ...

The second situation is shown below:

   (Thread 1)                 |      (Thread 2)
nfcmrvl_fw_dnld_start         |
 ...                          |
 mod_timer                    |
 (wait a time)                |
 fw_dnld_timeout              |  nfcmrvl_nci_unregister_dev
   fw_dnld_over               |   nfcmrvl_fw_dnld_abort
    release_firmware          |    fw_dnld_over
     kfree(fw) //(1)          |     release_firmware
     ...                      |      kfree(fw) //(2)

The third situation is shown below:

       (Thread 1)               |       (Thread 2)
nfcmrvl_nci_recv_frame          |
 if(..->fw_download_in_progress)|
  nfcmrvl_fw_dnld_recv_frame    |
   queue_work                   |
                                |
fw_dnld_rx_work                 | nfcmrvl_nci_unregister_dev
 fw_dnld_over                   |  nfcmrvl_fw_dnld_abort
  release_firmware              |   fw_dnld_over
   kfree(fw) //(1)              |    release_firmware
                                |     kfree(fw) //(2)

The firmware struct is deallocated in position (1) and deallocated
in position (2) again.

The crash trace triggered by POC is like below:

BUG: KASAN: double-free or invalid-free in fw_dnld_over
Call Trace:
  kfree
  fw_dnld_over
  nfcmrvl_nci_unregister_dev
  nci_uart_tty_close
  tty_ldisc_kill
  tty_ldisc_hangup
  __tty_hangup.part.0
  tty_release
  ...

What's more, there are also use-after-free and null-ptr-deref bugs
in nfcmrvl_fw_dnld_start. If we deallocate firmware struct, gpio or
set null to the members of priv->fw_dnld in nfcmrvl_nci_unregister_dev,
then, we dereference firmware, gpio or the members of priv->fw_dnld in
nfcmrvl_fw_dnld_start, the UAF or NPD bugs will happen.

This patch reorders destructive operations after nci_unregister_device
in order to synchronize between cleanup routine and firmware download
routine.

The nci_unregister_device is well synchronized. If the device is
detaching, the firmware download routine will goto error. If firmware
download routine is executing, nci_unregister_device will wait until
firmware download routine is finished.

Fixes: 3194c6870158 ("NFC: nfcmrvl: add firmware download support")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
CVE: CVE-2022-1734
CWE: CWE-416
Vulnerability description: A flaw in Linux Kernel found in nfcmrvl_nci_unregister_dev() in drivers/nfc/nfcmrvl/main.c can lead to use after free both read or write when non synchronized between cleanup routine and firmware download routine.

Project: linux
File: main.c

static int nfcmrvl_nci_fw_download(struct nci_dev *ndev,
				   const char *firmware_name)
{
	return nfcmrvl_fw_dnld_start(ndev, firmware_name);
}

Project: linux
File: main.c

static int nfcmrvl_nci_setup(struct nci_dev *ndev)
{
	__u8 val = 1;

	nci_set_config(ndev, NFCMRVL_PB_BAIL_OUT, 1, &val);
	return 0;
}

Project: linux
File: main.c

void nfcmrvl_chip_reset(struct nfcmrvl_private *priv)
{
	/* Reset possible fault of previous session */
	clear_bit(NFCMRVL_PHY_ERROR, &priv->flags);

	if (gpio_is_valid(priv->config.reset_n_io)) {
		nfc_info(priv->dev, "reset the chip\n");
		gpio_set_value(priv->config.reset_n_io, 0);
		usleep_range(5000, 10000);
		gpio_set_value(priv->config.reset_n_io, 1);
	} else
		nfc_info(priv->dev, "no reset available on this interface\n");
}

Project: linux
File: main.c

static int nfcmrvl_nci_open(struct nci_dev *ndev)
{
	struct nfcmrvl_private *priv = nci_get_drvdata(ndev);
	int err;

	if (test_and_set_bit(NFCMRVL_NCI_RUNNING, &priv->flags))
		return 0;

	/* Reset possible fault of previous session */
	clear_bit(NFCMRVL_PHY_ERROR, &priv->flags);

	err = priv->if_ops->nci_open(priv);

	if (err)
		clear_bit(NFCMRVL_NCI_RUNNING, &priv->flags);

	return err;
}

Project: linux
File: main.c

int nfcmrvl_nci_recv_frame(struct nfcmrvl_private *priv, struct sk_buff *skb)
{
	if (priv->config.hci_muxed) {
		if (skb->data[0] == NFCMRVL_HCI_EVENT_CODE &&
		    skb->data[1] == NFCMRVL_HCI_NFC_EVENT_CODE) {
			/* Data packet, let's extract NCI payload */
			skb_pull(skb, NFCMRVL_HCI_EVENT_HEADER_SIZE);
		} else {
			/* Skip this packet */
			kfree_skb(skb);
			return 0;
		}
	}

	if (priv->ndev->nfc_dev->fw_download_in_progress) {
		nfcmrvl_fw_dnld_recv_frame(priv, skb);
		return 0;
	}

	if (test_bit(NFCMRVL_NCI_RUNNING, &priv->flags))
		nci_recv_frame(priv->ndev, skb);
	else {
		/* Drop this packet since nobody wants it */
		kfree_skb(skb);
		return 0;
	}

	return 0;
}

Project: linux
File: main.c

void nfcmrvl_chip_halt(struct nfcmrvl_private *priv)
{
	if (gpio_is_valid(priv->config.reset_n_io))
		gpio_set_value(priv->config.reset_n_io, 0);
}

Project: linux
File: main.c

int nfcmrvl_parse_dt(struct device_node *node,
		     struct nfcmrvl_platform_data *pdata)
{
	int reset_n_io;

	reset_n_io = of_get_named_gpio(node, "reset-n-io", 0);
	if (reset_n_io < 0) {
		pr_info("no reset-n-io config\n");
	} else if (!gpio_is_valid(reset_n_io)) {
		pr_err("invalid reset-n-io GPIO\n");
		return reset_n_io;
	}
	pdata->reset_n_io = reset_n_io;

	if (of_find_property(node, "hci-muxed", NULL))
		pdata->hci_muxed = 1;
	else
		pdata->hci_muxed = 0;

	return 0;
}

Project: linux
File: main.c

void nfcmrvl_nci_unregister_dev(struct nfcmrvl_private *priv)
{
	struct nci_dev *ndev = priv->ndev;

	nci_unregister_device(ndev);
	if (priv->ndev->nfc_dev->fw_download_in_progress)
		nfcmrvl_fw_dnld_abort(priv);

	nfcmrvl_fw_dnld_deinit(priv);

	if (gpio_is_valid(priv->config.reset_n_io))
		gpio_free(priv->config.reset_n_io);

	nci_free_device(ndev);
	kfree(priv);
}

Project: linux
File: main.c

static int nfcmrvl_nci_close(struct nci_dev *ndev)
{
	struct nfcmrvl_private *priv = nci_get_drvdata(ndev);

	if (!test_and_clear_bit(NFCMRVL_NCI_RUNNING, &priv->flags))
		return 0;

	priv->if_ops->nci_close(priv);

	return 0;
}

Project: linux
File: main.c

struct nfcmrvl_private *nfcmrvl_nci_register_dev(enum nfcmrvl_phy phy,
				void *drv_data,
				const struct nfcmrvl_if_ops *ops,
				struct device *dev,
				const struct nfcmrvl_platform_data *pdata)
{
	struct nfcmrvl_private *priv;
	int rc;
	int headroom;
	int tailroom;
	u32 protocols;

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return ERR_PTR(-ENOMEM);

	priv->drv_data = drv_data;
	priv->if_ops = ops;
	priv->dev = dev;
	priv->phy = phy;

	memcpy(&priv->config, pdata, sizeof(*pdata));

	if (gpio_is_valid(priv->config.reset_n_io)) {
		rc = gpio_request_one(priv->config.reset_n_io,
				      GPIOF_OUT_INIT_LOW,
				      "nfcmrvl_reset_n");
		if (rc < 0) {
			priv->config.reset_n_io = -EINVAL;
			nfc_err(dev, "failed to request reset_n io\n");
		}
	}

	if (phy == NFCMRVL_PHY_SPI) {
		headroom = NCI_SPI_HDR_LEN;
		tailroom = 1;
	} else
		headroom = tailroom = 0;

	if (priv->config.hci_muxed)
		headroom += NFCMRVL_HCI_EVENT_HEADER_SIZE;

	protocols = NFC_PROTO_JEWEL_MASK
		| NFC_PROTO_MIFARE_MASK
		| NFC_PROTO_FELICA_MASK
		| NFC_PROTO_ISO14443_MASK
		| NFC_PROTO_ISO14443_B_MASK
		| NFC_PROTO_ISO15693_MASK
		| NFC_PROTO_NFC_DEP_MASK;

	priv->ndev = nci_allocate_device(&nfcmrvl_nci_ops, protocols,
					 headroom, tailroom);
	if (!priv->ndev) {
		nfc_err(dev, "nci_allocate_device failed\n");
		rc = -ENOMEM;
		goto error_free_gpio;
	}

	rc = nfcmrvl_fw_dnld_init(priv);
	if (rc) {
		nfc_err(dev, "failed to initialize FW download %d\n", rc);
		goto error_free_dev;
	}

	nci_set_drvdata(priv->ndev, priv);

	rc = nci_register_device(priv->ndev);
	if (rc) {
		nfc_err(dev, "nci_register_device failed %d\n", rc);
		goto error_fw_dnld_deinit;
	}

	/* Ensure that controller is powered off */
	nfcmrvl_chip_halt(priv);

	nfc_info(dev, "registered with nci successfully\n");
	return priv;

error_fw_dnld_deinit:
	nfcmrvl_fw_dnld_deinit(priv);
error_free_dev:
	nci_free_device(priv->ndev);
error_free_gpio:
	if (gpio_is_valid(priv->config.reset_n_io))
		gpio_free(priv->config.reset_n_io);
	kfree(priv);
	return ERR_PTR(rc);
}

Project: linux
File: main.c

static int nfcmrvl_nci_send(struct nci_dev *ndev, struct sk_buff *skb)
{
	struct nfcmrvl_private *priv = nci_get_drvdata(ndev);

	nfc_info(priv->dev, "send entry, len %d\n", skb->len);

	skb->dev = (void *)ndev;

	if (priv->config.hci_muxed) {
		unsigned char *hdr;
		unsigned char len = skb->len;

		hdr = skb_push(skb, NFCMRVL_HCI_EVENT_HEADER_SIZE);
		hdr[0] = NFCMRVL_HCI_COMMAND_CODE;
		hdr[1] = NFCMRVL_HCI_OGF;
		hdr[2] = NFCMRVL_HCI_OCF;
		hdr[3] = len;
	}

	return priv->if_ops->nci_send(priv, skb);
}